"Bugfix" (i.e. feature request in disguise!) [#26772] Delta Scaling,

Rotation and Location don't have Keying Sets

Added Keying Sets for Delta Loc/Rot/Scale settings (aka dLoc/dRot).
These settings could already be found in the Object properties, under
the collapsed "Delta Transforms" panel.

I've added these to the end of the Keying Sets list, since adding any
earlier will end up breaking active Keying Set setting in older files.
Besides, these settings aren't that frequently used either...

release/scripts/modules/keyingsets_utils.py

@@ -52,9 +52,12 @@ def path_add_property(path, prop):
 # Poll Callbacks
 
 
-# selected objects
+# selected objects (active object must be in object mode)
 def RKS_POLL_selected_objects(ksi, context):
-    return context.active_object or len(context.selected_objects)
+    if context.active_object:
+        return context.active_object.mode == 'OBJECT'
+    else:
+        return len(context.selected_objects) != 0
 
 
 # selected bones
@@ -84,6 +87,11 @@ def RKS_ITER_selected_item(ksi, context, ks):
     else:
         for ob in context.selected_objects:
             ksi.generate(context, ks, ob)
+            
+# all select objects only
+def RKS_ITER_selected_objects(ksi, context, ks):
+    for ob in context.selected_objects:
+        ksi.generate(context, ks, ob)
 
 ###########################
 # Generate Callbacks